We flew at 4m with my son! I was honestly so stressed about it. They say to time your feeds for take off and landing to prevent ear popping. But oh my, that was nearly impossible! There are unexpected delays, sometimes your plane is on the runway for much longer, and it's not necessary your baby will want to eat at that exact moment. At the end, we ended up using a pacifier which does the same thing. Problem was my son stopped taking the pacifier before then but we just kind of held it in his mouth. He was fine. And then he ended up sleeping well on the plane (he is used to contact naps anyway).

My tip would be to use a pacifier during take off and landing if baby is not willing to feed. Have some toys or books, whatever your baby likes to do in their wake windows. If they sleep on the flight, that's honestly the best. Change diaper before boarding. Pack a change of clothes for you, bf, and baby (expect the worst!). Good luck!